Bagmaking apparatus



` Dec. 16, 1952 N. H. NYE ErAx. 2,621,705

BAGMAKING APPARATUS Filed April 24, 1951 2 SHEETS-#smh 2 Patented Dec. 16, 1952 BAGMAKIN G APPARATUS Norman H. Nye Vand` Ralph W. Penn, Cuyahoga Falls, and Clarence C. Ensinger and Charles H. Sorrick, Jr., Kent, Ohio Application April.24, 1951, Serial N0. 222,711

6 Claims.

This invention relates to apparatusfor making articles from plastic sheet or strip material, and especially to apparatus for making bags from such strip material.

In the production of small articles, such as bags, from plastic sheet material, it will be realized that in most commercial operations, the bags are made in large numbers and that the cost of such bags must be reduced to an absolute minimum in order to be competitive with similar bags made from paper, or other materials. Accordingly, in the fabrication of such plastic bags, it is necessary that an automatic, simple apparatus be used wherever possible to form the bags accurately, rapidly and economically. Furthermore, these bags ymust be produced in a uniform manner by effective, properly functioning apparatus to insure vthat a minimum of rejects or spoiled materials is produced when making a production run of any given bag.

The general object of the present invention is to provide apparatus of the class referred to hereinabove that are characterizedby rapid automatic'operation and production of high `quality bags from plastic strip material by relatively simple inexpensive apparatus.

Another object of the invention is to provide apparatus that simultaneously cuts folded plastic material and seals the severed edges together.

Another object of the invention is'to provide apparatus of the class described Which are capable of the continuous, rapid, and automatic production of bags of a varietyof sizes from folded, elongate thermoplastic strip material.

Another object of the invention is to provide relatively inexpensive apparatus for making articles of the class described, which apparatus is adapted for operation Vover long service periods with a minimum of maintenance thereon.

The foregoing and other objects and advantages of the invention will be made more apparent as the specication proceeds.

For a better understanding of the present invention, attention is directed to the accompanying drawings, wherein:

Fig. l is a front elevation o-f apparatus embodying the principles of the invention;

Fig..2 is a fragmentary right side elevation of the upper portion of the apparatus of Fig. 1;

Fig. 3 is a perspective View of a bag made in accordance with the teachings of the invention; and

Fig. l is a cross-sectional view of the bag of Fig. 3,*and taken on line'l'V--V of Fig. 3.

Broadly speaking, the apparatus of the invenframe 2.

tion comprises a rotatable cylinder which has a plurality of electro-conductive Wires on the surface of the cylinder extending axially thereof in circumferentially spaced relation, means for feeding elongate thermoplastic strip material to the cylinder for passage over the surface thereof and contacting the Wires thereon, and means for supplying electrical energy to these Wires at predetermined times and in sufficient quantity to heat the Wires to cause them to fuse the parts of the thermoplastic strip contacting same and occasion severance of portions of the strip from the remainder of the strip, and usually the simultaneous formation of a bag of the desired size.

For a better .understanding of the invention, reference should be had to the details of the structure shown in the drawings, and apparatus for forming bags or other articles from thermoplastic strip material or the'like is' shown and is indicated in general by the numeral I. This apparatus I includes a frame 2 on which a suitable cylinder 3 is journaled by means of a shaft 4 carried in bearings 4a removably fixed to the The frame is laterally slotted at 2a to allow the shaft 4, cylinder 3, and bearings 4a to be removed as a unit to allow for the substitution of adiiferent sized cylinder 3 to make different L@ized bags when desired. The cylinder 3 has an velectrical andheat insulating material, such as asbestos, on the surface thereof. Usually the frame 2 carries a .suitable drive motor 5 on a lower portion thereof, which motor 5 connects through a reducing sheave 6 to a drive gear box 'I bymeans of belts 8 and 9. A drive sheave I is suitably secured to a protruding end portion of the shaft 4 and it engages an output sheave 'la of the drive gear box 'I by a belt Il, so that the cylinder 3 can be rotated at any ,desired speed from the drive motor 5. Of course,

any desired adjustment can be made in the connection of the drive motor 5 4to the cylinder 3 to vary, or control the speed thereof.

In order to ycontrol and supply the strip material, such as a thermoplastic strip I2, which is to be fabricated into bags by the apparatus I, usually vthe frame 2 has brackets I3 secured thereto and extending therefrom. The strip I2 has been previously folded longitudinally as hereinafter more particularly described. The brackets I3 support a roll of the thermoplastic strip I2 by means of a shaft I 4 engaging such roll and being supported on the brackets I3 at opposite ends of such roll of material. The thermoplastic sheet I2 is led from the roll there- Aof around a guide roll I5 and thereafter is deposited on the surface of the cylinder 3. The

guide roll I5 usually is carried by a pair of pivotally positioned arms I6, one of which is engaged with each of the brackets I3 and normally extends substantially vertically upwardly therefrom. These guide arms I6 are pivotally engaged with the brackets I3 by pins I1, or similar means, and coil springs I8 or their equivalents urge the arms I6 inwardly towards the cylinder 3. Usually the arms I6 carry a pressure roll I9 that is suitably journaled thereon and extends therebetween and bears against the portion of the strip material I2 being fed to the cylinder 3.

Usually it is desirable and necessary to retain the strip I2 in relatively tight contact with the surface of the cylinder 3V to assist in the bag forming and severing action and to this end, a plurality of discs are positioned on a shaft 2| which is journaled in and extends between spaced portions of the frame 2 above the cylinder 3 for positioning the discs so that their peripheral surfaces engage the strip I2 and force the thermoplastic material snugly against the surface of the cylinder 3. The vertical position of the shaft 2| can be adjusted by screws 2|a so as to allow for the substitution of a different ydiameter cylinder 3 in the apparatus.

Preferably the discs 28 are driven so that the surface speed thereof is greater than the speed of the surface of the cylinder 3 and this aids in holding the plastic tightly against the heating wires on the cylinder as hereinafter described. Accordingly, suitable connection means are provided for driving the shaft 2| and the discs 28 carried thereby at a greater surface speed than the cylinder 3. Such means are shown as comprising a pair of gears 22 and 23 that are journaled on a support arm 24 which is engaged with one side of the frame 2. Usually this support arm is provided with an arcuate slot 25 in a lower portion thereof and cap screws 26 or equivalent means, extend through the slot 25 and engage the frame 2 to position the support arm 24 in an adjustable manner. Such gears 22 and 23 engage, respectively, with gears 21 and 28 that are suitably carried by the shafts 4 and 2| at corresponding ends thereof so that a positive drive connection is provided between the shaft 4 and the shaft 2|. By changing gear 28 on shaft 2| to a different size, the surface speed of the discs 20 is changed to take care of the change of speed necessary when a different diameter cylinder 3 is utilized. Idler gears 22 and 23 swing as a unit with arm 24 about gear 21 to allow a different size gear 28 to be substituted.

As an important feature of the present invention, the cylinder 3 normally carries on its surface a plurality of axially extending electroconductive heating wires 29. These wires 29 are bare and are positioned in parallel but circumferentially spaced relation to each other with the circumferential spacing between the adjacent pairs of wires 29 determining the width of a bag or like article beingl formed on the apparatus of the invention. Usually one end of each of the wires 29 is suitably secured to a commutator segment 29ad carried in insulated relation on the end of the cylinder 3 adjacent the sheave I 0. Preferably these wires are maintained in taut positions on the surface of the cylinder 3 and such result may be obtained by engaging the opposite end portions of the wires V29 individually to coil springs 30. The opposite ends of such 4 springs 30 are suitably secured to a disc 3| that is carried by and secured to the shaft 4 intermediate the remaining end of the cylinder 3 and the adjacent portion of the frame 2.

Usually flexible pigtail leads connect the actual ends of the wires 29 to the disc 3| and through it are grounded to the shaft 4, but the coil springs 30 maintain the wires in tight or taut condition on the surface of the cylinder.

Power is supplied to the wires 29 in any suit-4 able manner and preferably power is only sup-- plied to such wires for a portion of the circum ferentia1 movement of the surface of the cylinderv 3 since such wires rapidly heat up to a high enough temperature to fuse and sever the portions of the thermoplastic strip I2 contacting same. Fig. l of the drawings shows that a suitable variable voltage transformer 32 or other type of a variable voltage control is provided which has suitable electrical energy supplied thereto by electric leads 33 and 34. The transformer connects through electric leads 35 and 33 to brushes 31 and 38, which engage with the commutator segments 29a in turn, and with the shaft 4 respectively. The brush 31 is, of course, electrically insulated from the frame 2. During the rotation of the cylinder 3, the brush 31 is brought in turn into electrical contact with the commutator segments 29EL and the brush stays in contact with each segment for a portion of the rotation of the cylinder 3, usually through an arc of about 60. This closes a circuit back through shaft 4 and brush 38. The transmission of electrical energy to each wire 29 for a given arc of its travel provides sufficient power to fuse the portion of the strip contacting the wire and thus sever the strip into bag length and simultaneously seal the strip edge to form a bag edge.

Normally in feeding thermoplastic strip material to the cylinder 3, the strip has been longitudinally folded on itself to provide a folded edge I2c and two portions I2a and I2b thereof that are in superimposed relation with the portion I2a being a little wider than the portion I2b to facilitate inserting articles into the bag to be produced therefrom and to aid in later sealing same, if desired. The action in melting through the folded thermoplastic strip I2 with the heated wire is such that both portions I2a and I2b of the strip are not only severed but the severed edges are fused and tightly sealed together. These severed portions of the thermoplastic strip I2 are indicated at I2d, I2e in the drawing so that the heated wires of the apparatus normally cut through or fuse longitudinally spaced portions of the strip I2 and produce a bag at each section oi strip severed from the original continuous elongate strip by the apparatus of the invention.

Suitable means (not shown) are disclosed and claimed in our separate (zo-pending application Serial No. 222,712 for automatically removing the bags or other articles formed from the surfaces of the cylinder 3.

Obviously any desired thin plastic material can be used in the apparatus, such as films of polyethylene, rubber hydrochloride, vinyl and the like.

While one complete embodiment of the apparatus of the invention has been disclosed herein, it will ybe appreciated that modification thereof and of the method of the invention may be resorted to without departing from the scope of the invention as defined by the appended claims.

What is claimed is:

1. In apparatus for making bags from thin thermoplastic sheeting, a frame, a shaft journaled on said frame, a cylinder carried by said shaft, means for rotating said cylinder, a plurality of electroconductive wires on the surfaces of said cylinder and extending axially thereof in circumferentially spaced relation, roller means forr pressing strip material against said cylinder', drive means for rotating said last named roller means at a greater peripheral speed than said cylinder, and means for supplying electric current to said wires at desired times.

2. In apparatus for making bags from thin thermoplastic strips, or sheeting, a frame, a shaft journaled on said frame, a cylinder carried by said shaft, means for rotating said cylinder, a plurality of electroconductive wires on the surfaces of said cylinder and extending axially Vthereof in circumferentially spaced relation, a

longitudinally folded thermoplastic strip being carried by said cylinder, roller means for pressing such strip material against said cylinder, adjustable speed drive means connecting said driven cylinder to said roller means to drive said rollei means at a predetermined peripheral speed with relation to the peripheral speed of said cylinder, and means for supplying electric current to said wires for fusing spaced parallel sections of said folded strip to sever a portion of the strip therefrom.

3. Apparatus for making bags from plastic film including a frame, a cylinder removably journaled in the frame, a plurality of heating wires circumferentially spaced on the cylinder in substantially axially parallel position thereon, spring meansl for holding the wires taut, means for supporting a roll of longitudinally folded plastic film on the frame, roller means for guiding the end of the roll of lrn over the cylinder, means for rotating the cylinder, adjustable gear means for driving the roller means from the cylinder and at a slightly greater surface speed than the cylinder to hold the film tight on the cylinder, and means for applying selective amounts of heating current to the wires through a portion of the arc of contact between the film and wires to sever the film into bags Whose edges have been severed and heat sealed by the wires.

4. Apparatus for making bags from plastic iihn including a frame, a heat resistant cylinder journaled in the frame, a plurality of heating wires circumferentially spaced on the cylinder in substantially axially parallel position thereon, means for supporting a roll of longitudinally folded plastic film on the frame, roller means for guiding the end of the roll of film over the cylinder, means for rotating the cylinder, adjustable gear means for driving the roller means from the cylinder and at a slightly greater surface speed than the cylinder to hold the film tight on the cylinder, and means for applying heating current to the wires through a portion of the arc of contact between the film and wires to sever the film into bags whose edges have been severed and heat sealed by the wires.

5. Apparatus for making bags from plastic hn including a frame, a cylinder journaled in the frame, a plurality of heating wires circumferentially spaced on the cylinder in substantially axially parallel position thereon, means for supplying a strip of longitudinally folded plastic film, roller means for guiding the end of the strip of film over the cylinder, means for rotating the cylinder, adjustable gear means for driving the roller means from the cylinder andat a slightly greater surface speed than the cylinder to hold the film tight on the cylinder, and means for applying heating current to the wires through a portion of the arc of contact between the film and wires to sever the film into bags `whose edges have been severed and heat sealed by the wires.

6. Apparatus for making bags from plastic film including a frame, a cylinder journaled in the frame, at least one heating Wire in substantially axially parallel position on the cylinder, means for supplying a strip of longitudinally folded plastic lm, roller means for guiding the end of the strip of film over the cylinder, means for rotating the cylinder, gear means for driving the roller means at a slightly greater surface speed than the cylinder, and means for applying heating current to the wire through a portion of the arc of contact between the film and wire to sever the film into bags whose edges have been severed and heat sealed by the Wire.

NORMAN H. NYE. RALPH W. PENN. CLARENCE C. ENSINGER. CHAS. H. SORRICK, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,185,647 Penn et al. Jan. 2, 1940 2,229,121 Nye et al Jan. 21, 1941 

